The Efficacy of Ultraviolet Light In The Continuous Decontamination of Health Care Associated Pathogens

The Efficacy of Ultraviolet Light: A lighting system for continuous decontamination of health care–associated pathogens on surfaces.


  • Ultraviolet-A (UV-A) light has antimicrobial activity, and low doses may be safe.
  • We tested a commercial UV-A light fixture intended for use in health care settings.
  • The UV-A device reduced bacteria and viruses, but not spores, on steel carriers.
  • UV-A exposure from a ceiling light fixture reduced pathogens on medical equipment.
  • UV-A could provide continuous low-level decontamination of surfaces in health care.


We found that ultraviolet-A (UV-A) light exposure resulted in a modest reduction in recovery of methicillin-resistant Staphylococcus aureus (MRSA), Candida auris, bacteriophage MS2, and bacteriophage Phi X174, but not Clostridioides difficile spores, on steel disk carriers.

Four hours of UV-A exposure from a ceiling light fixture resulted in a significant reduction in pathogenic microorganisms recovered from in-use medical equipment.

These findings suggest that UV-A could be useful as a means to provide continuous low-level decontamination of surfaces in health care facilities.

Ultraviolet-A lightEnvironmentMethicillin-resistant Staphylococcus aureusStethoscope Contaminated environmental surfaces are an important source of transmission of health care–associated pathogens.

Unfortunately, performance of manual cleaning and disinfection is often suboptimal. Automated room decontamination devices such as ultraviolet-C (UV-C) light devices can be effective as an adjunct to routine cleaning.

However, UV-C room decontamination devices cannot be used when people are present and re-contamination occurs quickly after device operation.

Thus, there is a need for effective approaches that provide continuous and safe decontamination of surfaces while people are present.

Ultraviolet-A (UV-A) light at 365-nm wavelength has been shown to have antimicrobial activity against pathogens such as Escherichia coli and Candida albicans.

In contrast to UV-C, UV-A is present in sunlight and in modest doses may be safe for use when people are present.

A commercial UV-A light fixture that is intended for use in health care settings is currently in development.

In the current study, we examined the efficacy of UV-A light in reducing microorganisms on carriers and on portable medical equipment.

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